Spark-plug.



J. J, MCINTYRE. SPARK PLUG.

APPLICATION FILED new. 31, 1911.

1,641,835. Patented 002.2%1912 WITNESSES d I I INVENTOR Am 7 IJohnJMc/Wiyre ing and having an enlargement SPARK-PLUG.

Specification of Letters Patent.

Patented Oct. 22, 1912.

Application filed October 31, 1911. Serial No. 657,702.

To all whom it may concern:

Be it known that I, JOHN J. MGINTYRE, a citizen oi the United States,and a resident of Hartford, in the county of dartford and State ofConnecticht, have invented certain new and useful Improvements in Spark-Plugs, of which. the following is a specifics tion.

The object of this invention is to produce a spark plug for use inexplosive engines and the like having featuresof novelty and advantage,and the invention relates particularly to the means for lain plug inplace in the ing the bushing on to the invention relates to the trodes.v

In the drawings: Figure 1 is an elevation of a plug made in accordancewith my invention, the shell and bushing being shown in central verticalsection. Fig. 2 is a detail View of a modified form'of bushing. Fig. 25is adetail sectional view showing on an enlarged scale the manner oflocking the'bushing in place.

Referring to the drawings, a denotes the shell usually made of suitablemetal and having a threaded one which is screwed into the cylindercasing to present the electrodes properly within the cylinder.

7) is ihcplug of insulating material, as porcelain, fitting centrallywithin the cuswhich forms a shoulder to rest upon a shoulder (Z in theshell, there lacing interposed between these two shoulders a. suitablegasket 0 to produce 2. hcrnml'ic seal between the plug and shell whenthe plug is forced down into place by the bushing f. This bushing fitsdown over the plug as shown and its lower end is beveled and rests upona split metal ring 7, which lies on the upper side of the enlargement 0on the plug. The plug is enlarged slightly to i in shoulder 2. andbetween the end oi the luishing and the shoulder a metallic ring issprung alter the bushing is located, to prevent the bushing from comingoff of the plug when the latter is removeu from the shell. The bushingis threaded into a socket in the upper end of the shell shell and forholdlug and also'the rorm of the elecaudit will he noted that the lowerend of this socket is undercutas indicated at is. This bushing may bemade of soft or hard metal. Wherl soft metal is used the ring 9 shouldbe of a relatively harder metal so that when the bushing is screwed downits securing the porcebeveled end comes into contact with the ring 9,causing the end of the bushing to be spread into the undercut portion isand thus lock the bushing in place against accidental disengagement. Thering g is preferably non-rotatable upon the plug, thus relieving themore fragile porcelain from the combined turning and crowding effectandso minimizing the liability of breaking the plug when it is being setinto place in the shell which brings the porcelain always to correctposition within the shell. In order to insure solar as possible that thering shall be non-rotatable on the plug itis' split so as to make itresilient causing it to hug the plug when forced down by the bushin Insome cases where the plug is unususlly' smooth the engagement of thebushing with the ring may cause it to rotate on the plug. This is whatmight be termed an unusual condition and is not the preferred mode ofoperation. 'When the bushing is made of hard material, as drawn steeltubing, its lower edge is slotted as indicated clearly in vFig. 2 sothat when it comes in contact with the ring 9 it will he sprung out intothe undercut part 7-? and form a lock for the bushing. I s

By this construction I have provided a spark plug in which the porcelainplug can be removed from the shell and the bushing held in position onthe plug and when the plug isin place in the shell it is securely lockedagainst accidental disengagement.

That part of: the invention relating to the electrodes is clearlyillustrated in the drawings and consists in forming the negativeelectrodes 10-10 with their tips curved so that their ends are presentedto the end of the positive electrode 11. Under the influence of the heatoccasioned by the operation oi the engine the electrodes 10-40 tend tounwind or straighten out and, although the amount of movement occasionedis slight, nevertheless, it provision is not made for alwaysnuiintuining the sparking distance between the positive and negativeelectrodes uniform, the ignition system is affected. By forming thenegative electrodes as illustrated herein the unwinding or straighteningout of these electrodes moves their ends by the end of the positiveelectrode but during this movement the sparking distance is not altered,with the result that the condition of the ignition system can hemaintained substantially uniform.

ll claim as my invention:

1. In a device of the olassspecified,a shall,

a plug of insulating material located therein and having embedded in ita rod ofconducting material, a gasket interposed between engagingshoulders on the shell and plug, a bushing rotatably mounted on the Yplug and having threaded engagement with the shellpzmd meansnon-rotatable on the plug but cooperating with the end of said bushingtolock said bushing to said shell.

2. l n a device of the class specified, a shell,

I a plug of insulating material located therein, a gasket interposedbetween engaging shoulders on the shell and. plug, a bushing rotatablymounted on the plug and having threaded 'erigagen'ient with the shell,and

means for spreading the lower end of said bushing for the purposesspecified.

3. In a device of the character described, a shell having a centralaperture extending therethro-ugh, the upper part of said aperture beingenlarged to form a socket having a threaded Wall and an undercut portionbeneathsaid threads,a plug of insulating material located in saidaperture and resting on a shoulder and having embedded therein a, rod ofconducting material, a ringi-nonrotatable on said plug, a bushinsurrounding said plug and having three ed engagement with said shell,the lower end of said bushing being yielding and adapted to be spreadinto the undercut portion of the socket by said ring forthe purposedescribed.- i

4:. In a device of the character described,

a shoulder having a central aperture extending therethrough, the upperpart of said aperture'being enlarged to form a socket having a threadedWall and, an undercut portion beneath said, threads, a plug ofinsulating material located in said aperture and resting-on a shoulderand having em bedded therein a rod of conducting material, a bushingsurrounding said plug and having threaded engagement with said shell,

the lower end of said bushing being yielding,-

and means on said-plug coiiperating With the yielding lower end of saidbushing to spread it into the undercut portion of 'rthe socket for thepurpose described.

JOHN J. MolNTYRE.

Witnesses: I

M. E. UNnnzr, H. E. HART.

